1. Field of the Invention
The present invention relates to hinges and more particularly pertains to knee hinges which may be utilized on a knee brace and the like.
2. Description of the Prior Art
Knee braces are often utilized to support a user's knee when damage, disease, surgery, or the like has caused the knee to become weakened and unstable. Commonly, a knee brace is utilized both to provide extra support to the knee and to protect the knee from further injury. Priorly, knee braces of a variety of different forms have been employed to substantially support and/or strengthen a user's knee. A common method of creating additional support has been achieved by simply wrapping a material, such as an elasticized band, around a user's knee joint. Such a wrapping provides additional support to a user's knee, but only to a small degree.
Because of the modest support provided by this method, knee braces including hinges have been utilized to provide greater support to a user's knee. Substantially all of the prior art knee braces utilize similar leg supports, but differ both in their structure and in their use by subtle differences in the hinges that result in distinctive operating characteristics.
For example, a knee brace hinge is illustrated in U.S. Pat. No. 5,074,290 which utilizes a floating pivot point that allows the hinge to follow a natural motion of a user's knee.
Another knee brace hinge is described in U.S. Pat. No. 4,911,709 which utilizes a four bar linkage geometry that permits the available degree of knee flexion to be approximately 143 degrees.
U.S. Pat. No. 5,063,916 discloses a knee brace having a freecentric hinge that includes a locking mechanism to prevent hyperextension of a user's knee.
While all of the aforementioned patents serve to provide additional support and protection to a user's knee, none of the above patents discloses a knee hinge that will limit the range of knee flexion so as to reduce the danger presented should a user's knee buckle. A knee flexion of approximately 24 degrees will allow a user to walk or run normally and limiting the range of knee flexion to this amount will prevent a patient from falling if the user's knee should buckle. Therefore, it is desirable for a knee hinge to limit the available range of knee flexion to approximately 24 degrees.
It is also desirable for a knee hinge to incorporate other features as well. A knee hinge should selectively allow a full knee flexion range to permit a user to assume a conventional seating position and it should also allow a small amount of knee hyperextension for the purpose of allowing the user to assume and maintain a safe standing position. In addition, a knee hinge should be operable to selectively assist a user's knee in returning to a straightened position during walking and similar activities to compensate for damaged or weak supporting knee muscles.
Therefore, it can be appreciated that there exists a continuing need for a new knee hinge with selectively limited motion which can be utilized both to limit the range of knee flexion so as to reduce the danger from a user's knee buckling and to selectively allow a full knee flexion range which will permit a user to assume a conventional seating position. In this regard, the present invention substantially fulfills this need.